Hello, spicy friends. I'm about to have my network infrastructure rebuilt on L3 switches with a collapsed core design. On top of this, we're installing Ruckus WiFi APs all throughout the property to be able to accommodate up to 5,000 devices. This is a huge project for me, especially since I'm the only IT person in my organization, so I'm working with some consultants to have the backhauls done, install the switches, and place the access points. I'm going to be responsible for designing the VLANs and providing the services on the network that are necessary to run everything. One area that I'm a little unclear on is the DHCP side of things. Ideally, I'd like to have one large subnet (/19) to put all public WiFi devices into with DHCP services providing addresses for the entire subnet. What kind of limitations can I expect from a single-scoped DHCP server serving 5k addresses? Should I set up multiple servers each with their own scope within the subnet? If it's not feasible to have one large subnet, how should I design the VLANs and DHCP servers to serve the needs of a single SSID for public WiFi?

If you want to be able to accommodate up to 5,000 devices you are probably going to want to subnet this out into multiple subnets based on location of the AP's whether that be by floor, building, closet or whatever depending on your physical layout. One subnet with that many clients is very hard to manage and troubleshoot. The broadcast traffic would be heavy with this many users. The debate on the hard number is endless, I would direct that question to Ruckus. You can tie multiple VLANs back to one DHCP server with multiple scopes, Microsoft Server 2012 would handle the required load well.

If you want to be able to accommodate up to 5,000 devices you are probably going to want to subnet this out into multiple subnets based on location of the AP's whether that be by floor, building, closet or whatever depending on your physical layout. One subnet with that many clients is very hard to manage and troubleshoot. The broadcast traffic would be heavy with this many users. The debate on the hard number is endless, I would direct that question to Ruckus. You can tie multiple VLANs back to one DHCP server with multiple scopes, Microsoft Server 2012 would handle the required load well.

To add on to this, Windows Server DHCP will allow you to superscope. A superscope allows a DHCP server to provide leases from more than one scope to clients on a single physical network.